In addition to nineteen other sector armies, the 17th Sector Army was first activated by 22 BBY, the year that marked the beginning of a civil war—known as the Clone Wars—between the Galactic Republic and the Separatist Rebellion.Throughout the duration of the War, the Seventeenth was headquartered on the planet Vogel 7 and charged with the defense of the Dustig Oversector oversector. Like the other sector armies, the overall command of the Eighteenth was shared between a highly experienced Jedi General and a Governor-General who was appointed by the Supreme Chancellor of the Republic. By 19 BBY, the last year of the Clone Wars, the Governor-Generals evolved into a permanent class of regional governors known as the Moffs.
As the Clone Wars progressed, Chancellor Palpatine promoted Lynch Hauser to the rank of Moff, giving him control of the Seventeenth Army and the Dustig Oversector. The 17th Sector Army supported the 18th Sector Army in many campaigns.
After the conclusion of the Clone Wars, the Old Republic's twenty sector commands, including the Seventeenth Army, were retained by the newly-risen Galactic Empire. Under the New Order of Emperor Palpatine, Hauser ascended to the rank of Grand Moff. Much of the Imperial Era was marked by the Empire's massive military buildup and resulted in a vast army far larger than its Republic predecessor. Thus, the total infantry force of the Seventeenth Army and all other sector units were increased to approximately 1,572,864 troopers, most of whom were of natural birth as clones became marginalized into a minority status.